Plastic slide fastener



Sept. 1, 1953 J. N. KUZMICK PLASTIC sum: FASTENER 2 Sheefcs-Sheet loriginai Filed Nov. 17, 1945 6 3 0 T n m w E WW fi 1 2 J.. N. KUZMICKPLASTIC SLIDE FASTENER Sept. 1, 1953 z'sheets-sneet 2 Original FiledNov. 17, 1943 INVENTOR. JSePh-JKKU i076 Y &M y 3 operations.

Patented Sept. 1, 1953 PLASTIC SLIDE FASTENER Joseph N. Kuzmick,Clifton, N. J., assignor to Conmar Products Corporation, Newark, N. J.,a corporation of New Jersey Continuation of application Serial No.510,575, This application August 25, 1947, Serial No. 770,471

November 17, 1943.

. 6 Claims.

This invention relates to an improved method of manufacturing plasticslide fasteners, and more particularly to an improved method of makingsuch fasteners by molding the slide fastener elements directly onto thetapes to form the stringers. This application is a continuation of mycopending application Serial No. 510,575, filed November 17, 1943.

In prior methods of making plastic slide fasteners of the type in whichthe fastener elements are molded directly onto a tape, the top andbottom stops are made separately and are cemented onto the tape afterthe slide fastener elements are molded thereon. In completing theconstruction of a slide fastener, two stringers (with or withoutcemented-on top stops, depending on the method followed) are assembledwith a slider and are interlocked by the slider, after which the bottomstop is cemented to the two stringers, thus uniting the stringers attheir bottoms and forming the bottom stop for the slider.

This method is characterized by obvious disadvantages. The steps ofseparately making the top and bottom stops and of handling the same, theseparate steps of molding the slide fastener elements and then applyingand cementing the stops to the tape and the step of cementing-on of thebottom stops after the stringer pairs and sliders are assembled, involvean undesirable multiplying of manufacturing and assembling Furthermore,the cementing of the stops onto the tape is delicate work requiringextra time; and cemented-on stops, because of their insecure grip, are afrequent source of fault and failure.

The prime object of my present invention centers about the provision ofa method of manufacturing molded-on plastic slide fasteners and theproducts of such manufacture, in which the top and bottom stops may bemolded onto the tape and may be molded in the operation of molding theslide fastener elements onto the tape; the method and structure being,moreover, such that the stringers may thereafter be assem bled with theslider to form the complete slide fasteners, without the need, incidentto prior methods, of then applying or attaching any of the stops to thetapes. Thereby, the steps of separately making and handling the stops,the step of separately applying or cementing the stops to the tape, andcementing of the stops to the tape in assembled slide fasteners areentirely obviated, thus considerably reducing in number difficultmanufacturing and assembling steps, and molded-on stops, with theirsuperior gripping properties, are produced.

To the accomplishment of this object and these purposes and such otherobjects as may hereinafter appear, my invention relates to the method ofmanufacturing slide fasteners and the intermediate and end productsthereof as sought to be defined in the appended claims and as describedin the following specification taken together with the drawings, inwhich:

Fig. l is a view of a slide fastener stringer chain made in accordancewith the method of the present invention;

Fig. 2 is a view of a pair of stringers made pursuant to this method,positioned for mating or interlocking relation to form a slide fastener;

Fig. 3 is an elevational view of a form of top stop used;

Fig. 4 is a plan view thereof;

Fig. 5 is an elevational view of a form of bottom stop portion used;

Fig. 6 is a view illustrating the manner of assembling the stringer pairof Fig. 2 with slider;

Fig. 7 is a plan view illustrating the disposition of the bottom stopportions of the stringer pair of Fig. 6 after the assembling operationof Fig. 6;

Fig. 8 is a view of Fig. 7 illustrating the manner of uniting the bottomstop portions to complete the slide fastener assembly;

Fig. 9 is an elevational view illustrating the bottoms of the stringerpair (of Fig. 6) after the slider assembling operation;

Fig. 10 is a view similar to Fig. 9 and showing the construction afterthe bottom stop portions have been united to form a completed bottomstop;

Fig. 11 is a view corresponding to Fi 10, but showing the assembling oftwo so-called left stringers of the type shown in Fig. 10;

Fig. 12 is a view also corresponding to Fig. 10, but showing theassembling of two so-called right stringers of the type shown in Fig.10;

Fig. 13 is a view corresponding to Fig. 10, but showing a modifiedstructure of the bottom stop portions; and

Fig. 14 is a view of a still further modification again corresponding toFig. 10, but showing a modified form of bottom stop portions.

The essence of the method of manufacturing slide fasteners of thepresent invention consists in molding directly onto a tape, a group ofspaced slide fastener elements, a top stop at one end of the group, anda portion of a bottom stop at the other end of the group, therebyproducing by molding a slide fastener stringer completed by 5 top andbottom stop elements, then connecting 3 a pair of said stringers intointerlocked relation by means of a slider, and then uniting the twobottom stop portions into a completed bottom stop.

Fig. 1 of the drawings illustrates a stringer chain obtained in themolding step of the method; and Fig. 2 shows enlarged, a single pair ofstringers cut from two such chains ready for assembly to form acompleted slide fastener. The stringer chain comprises the spacedstringers S separated by the gaps G, each stringer consisting of a groupof slide fastener elements a top stop T and a bottom stop portion B, thetop stops T, T, the groups of slide fastener elements E, E,

and the bottom stop portions B, B, being all molded directly onto thetape Ta.

The molding of the slide fastener elements and the steps may preferablybe done by known injection methods. In making the stringer chain, theparts may be molded separately or in small or large groups; thus the topstop, the slide fastener elements and the bottom stop portion may beinjection molded step :by step, or a top stop, a group of slide fastenerelements and a bottom stop portion may be molded in one shot. It will beunderstood that any desired shape .or structure of bottom stop or topstop or slide fastener element may be used, and that these parts havebeen shown merely diagrammatically in the drawings except for thestructural principles herein discussed.

Figs. 6 to 8 of the drawings illustrate the assembly of a stringer pairand completing the making of .a slide fastener following the moldingstep of the method. A pair of stringers SL and SR, one a so-called left.stringer and the other a so-called right stringer, such as morecompletely shown in Fig. 2 of the drawings, are assembled with andinterlocked by a conventional type of slider 20 after the manner shownin Fig. 6. The pulling up of the slider 20 in the direction indicated bythe arrow 22, or conversely, the pulling down of the stringers SL and.SE in the direction indicated by the arrows 24, causes the interlockingof the elements E, E, of the stringer pair and produces the assembledstringer pair and slider. The bottom stop .portions (now designated BLand BB to differentiate the left and right stop portions) first arethreaded through the slider 23, the bottom stop portions beingdimensioned so as to permit this threading through operation. The resultis a completed slide fastener assembly except for the fact that thebottom stop portions BL and BR are non-united, as is illustrated by Fig.7 of the drawings. The opposed faces 26 and 2 8 of the bottom stopportions BL and BR are then united by means of any suitable cement, thusforming the completed or unitary bottom stop shown in, Fig. 8 of thedrawings, the united or cemented faces being there designated by thedotted line 30.

The uniting of the two bottom stop portions BL and BR and the stagescorresponding to those depicted in Figs. 7 and 8 of the drawings arealso illustrated in Figs. 9 and 10 of the drawings, Fig. 9 depicting thebottom portions of the assembled slide fastener before they are cementedtogether, while Fig. 'liO illustrates the same after they are cementedtogether, producing the completed slide fastener.

Thus the method consists simply in molding directly onto tapes, theslide fastener elements, the top stops and the bottom stop portions asillustrated in Fig. 1 of the drawings, thereby producing by moldingslide fastener stringers such as is illustrated in Fig. 2 of thedrawings, then simply connecting a pair of said stringers intointerlocked relation by means of a slider as shown in Fig. 6 of thedrawings, and then uniting the two bottom stop portions into a completedbottom stop as illustrated in Figs. 8 or 10 of the drawings.

Thereby, slide fastener stringers of the plastic element type ma haveall the parts directly molded thereon and may be assembled requiringonly the cementing together of their bottom stop portions. And thereby,as outlined above, the .steps of separately making and handling thestops, the step of separately applying or cement- :ing the stops to thetape, and the cementing of the stops to the tape in assembled slidefasteners are obviated, and thereby molded-on stops with their superiorgripping properties are produced.

As already indicated, the stringers are made the form of left stringersSL and right stringers SR. These stringers have the same top stops Twhich may embody a construction as shown in Figs. .3 and 4 having thebody 32 and the tape encompassing jaws .34. The bottom stop portions BLand BR, similar in form in the embodiment shown in Figs. 1 to 1.0 mayhave a construction as shown in Fig. 5, having the body 36 and the tapeencompassing jaws 38. Due to the staggered arrangement of the elementson a stringer pair SL, SR (see Fig. 2), the num. ber .of fastenerelements on one of the stringers such as SL will exceed by one thenumber of elements on the other stringer. The lowermost left and rightelements EL and ER should, therefore, have a spacing respectively.fronrthe bottom stop portions so as to prevent any accidental unlockingof the slide fastener should any two stringers such as two leftstringers or two right ones be assembled into a slide fastener, but alsoto make the assembly of any two stringers possible.

This latter is illustrated in Figs. 9 to 12 of the draw'inges, where, inFigs. 9 and 10, the left stringer is shown assembled with a rightstringer, and where, in Fig. 11 two left stringers SL,, SL are shownassembled, while in Fig. 12 two right stringers SR, SR. are shownassembled. The spacing between elements is indicated in Fig. 10 as d,the thickness of an element as t, and

the pitch between elements (d-l-t) as P. The lowermost element EL ispreferably spaced from the bottom stop portion EBL by the distancebetween any two adjacent elements, namely, the distance d. The lowermostelement ER, (the right stringer) is spaced from the bottom stop portionBR by the distance indicated in Fig. 10 as d, which, it will be found,is equal to onehalf P (the pitch between two elements) plus d (thedistance or spacing between two elements).

With a construction of this nature, a left stringer SL is assemblablewith a right stringer SR as shown in Figs. 9 and 10 of the drawings, twoleft stringers SL, SL are assemblable as shown in Fig. 11 of thedrawings, and two right stringers are assemblable as shown in Fig. 12 ofthe drawings. In all of these arrangements any accidental unlocking ofthe fastener will be prevented or at least made difficult and each ofthese will permit the assembling of the stringers as clearly shown inFigs. 10 to 12 of the drawings, and the assembling of the same with theslider. The provision of the distance d makes the assembly of two leftstringers possible as shown in Fig. 11, and the provision of thedistance d makes the assembly of two right stringers possible as shownin Fig. 12.

Fig. 13 shows a left stringer SL and a right stringer SR in whichdifferent lengths of bottom stop portions are provided. -The bottom stopportion BL on the left stringer is identical with that shown in Figs. 1to 12 of the drawings, while the bottom stop portion BR of the rightstringer is made longer than the portion BL by one-half of the pitch P.In this constructional form, the bottom stop portion BR is spaced fromthe lowermost element ER by the same distance as the portion BL isspaced from the lowermost element EL, namely, the distance d. It will beevident from a comparison between Figs. 13 and 11 of the drawings thattwo left stringers of the type shown in Fig. 13 and two right stringersof the type shown in Fig. 13 may be assembled together, the partsclearing in the same way as is depicted byFig.11. I

In the Fig. 13 form of construction the distance between the bottomportions and the lowermost fastener elements of both stringers isshortened as much as possible, thus preventing an undesirable unlockingof the slide fastener at the bottom end, which unlockin might otherwiseoccur because of lack of support of the lowermost element of thefastener.

In Fig. 14 of the drawings I show a still further modification in whichthe advantages of Fig. 13 are carried out by the use, however, of abottom stop portion on a left stringer which is molded integrally withthe lowermost fastener element. In this form of the invention the leftstringer SL is provided with a bottom stop portion B which is moldedintegrally with the lowermost element E, while the right stringer SR isprovided with a bottom stop portion BR similar to that shown in Fig. 13and similarly spaced from the lowermost fastener element ER.

The manner of practicing the method of the present invention, the makingof the products thereof, and the advantages over prior art practice inthe manufacture of plastic fasteners in which the elements are directlymolded onto the tape will in the main be fully apparent from the abovedetailed description thereof.

The plastic fastener elements E (Fig. 1) are applied to the tape, and atthe same time a plastic top stop T is molded on the tape, and half of aplastic bottom stop B is molded on the tape. One method of moldingplastic elements on a tape molds all of the elements of a stringer atonce, the die having element cavities for a length of six inches forsix-inch fasteners, eight inches for eight-inch fasteners, etc. Afterthe die is opened, the tape is moved far enough to provide a gap space Gbetween stringers, as well as a new length of tape for the nextstringer. This molding method is well adapted for the present inventionbecause, in accordance with the present invention, each mold is thenprovided with additional cavities at each end to mold a top stop T, andhalf B of a bottom stop, all during a single molding operation. The topstops are dimensioned too large to pass through a slider.

After two such chains of stringers have been formed, they are cut intopairs of stringers. Each pair is passed through a slider, as shown inFig. 6. The halves of the bottom stop are readily able to pass throughthe slider, as shown in Fig. 6, and the elements of the two stringersare interlocked by the action of the slider, as shown in Fig. 9. At thistime the halves of the bottom stop are still separate, but cannot beleft that 6 way, for if pulled apart by even the slightest force, thefastener will open from the bottom.

It will be observed in Fig. 9 that the bottom stop halves are each asingle block of plastic material extending longitudinally of the tape,and that they have abutting faces of substantial area extendinggenerally longitudinally of the tape and adapted to be cemented directlytogether in face to face relation, as indicated in Fig. 10. By such acementing operation a complete nonseparable bottom stop is formed, andthe only operations needed to complete the slide fastener after theinitial molding operation, are to pass the stringers through a slider,and to then cement the halves of the bottom stop together. As much aspossible is accomplished in the molding operation, and very little workis needed thereafter.

It will be further apparent that changes may be made in the method andthe resulting product without departing from the spirit ofthe inventiondefined in the following claims.

I claim:

1. For a slide fastener, a pair of stringers, each stringer comprising atape, a group of spaced slide fastener elements, a top stop at one endof the group, and a portion of a bottom stop at the other end of thegroup, the bottom stop portion on one stringer being distant from. theadjacent fastener element on that stringer by the approximate distancebetween any two adjacent elements, and the bottom stop portion on theother stringer being distant from the adjacent fastener element on thatstringer by a distance substantially equalling one-half the pitchbetween two elements plus the distance between two elements, the saidtop stops, groups of fastener elements and bottom stop portions beingmolded onto their respective tapes.

2. A slide fastener unit comprising a stringer, said stringer consistingof a tape, a group of spaced slide fastener elements, a top stop at oneend of the group, and a portion of a bottom stop at the other end of thegroup, the bottom stop portion being distant from the next adjacentfastener element on the stringer by a distance substantially equallingone-half of the pitch between two elements plus the distance between twoelements, the said top stop, group of fastener elements and bottom stopportion being molded onto the tape.

3. A slide fastener comprising a pair of stringers, each stringercomprising a tape, a group of spaced slide fastener elements, a top stopat one end of the group, and a portion of a bottom stop at the other endof the group, the bottom stop portion on one stringer being distant fromthe adjacent fastener element on that stringer by the approximatedistance between any two adjacent elements, and the bottom stop portionon the other stringer being distant from the adjacent fastener elementon that stringer by a distance substantially equalling one-half of thepitch between two elements plus the distance between two elements, thesaid top stops, groups of fastener elements and bottom stop portionsbeing molded onto their respective tapes, and the bottom stop portionsof the two stringers being united into a completed single bottom stop.

4. For a slide fastener, a pair of stringers, each stringer comprising atape, a group of spaced slide fastener elements, a top stop at one endof the group, and a portion of a bottom stop at the other end of thegroup, the bottom stop portion of one stringer being distant from theadjacent) element on that stringer'by the approximate distance betweenany two adjacent elements, and the bottom stop portion on the otherstringer being longer than the bottom stop portion on the first stringersubstantially by onehalf of the pitch between two elements, and beingdistant from the adjacentelement on its stringer by the approximatedistance between two adjacent elements, the top stops, groups ofelements and bottom stop portions being molded onto their respectivetapes.

5.- A slide fastener comprising a pair of stringers, each stringercomprising a tape, a group of spaced slide fastener elements, a top stopat one end of the group, and a portion of a bottom stop atthe otherend'of the group, the bottom stop portion of one stringer being distantfrom the adjacent element on that stringer by the approximate distancebetween any two adjacent elements, the bottom stop portion on the otherstringer being longer than the bottom stop portion on the first stringersubstantially by onehalf of the pitch between two elements, and beingdistant from the adjacent element on its stringer by the approximatedistance between two adjacent elements, the top stops, groups ofelements and bottom stop portions being molded onto their respectivetapes, and the bottom stop portions of the two stringers being unitedinto a completed single bottom stop.

' 6.- For a slide fastener, a pair of stringers, each stringercomprising a tape, a group of spaced slide fastener elements, a top stopat one end of the'group, and a portion of a bottom stop at the other endof the group, the bottom stop portion of one stringer being integralwith the adj acent fastener element, on that stringer, and the bottomstop portion on the other string-er being spaced from the adjacentelement on its stringer, the top stops, groups of elements andbottomlstop portions being molded onto their respective tapes.

JOSEPH N. KUZMICK.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 2,18%,265 Winterhalter Dec. 19, 1939 2,186,774 Sundbaok Jan.9, 1940 2,219,165 Nedal Oct. 22, 1940

